大约有 44,000 项符合查询结果（耗时：0.0533秒） [XML]
Android: How to bind spinner to custom object list?
... has its own ID (the IDs are not equal to display sequence). When the user selects the name from the list the variable currentID has to be changed.
...
What is PostgreSQL explain telling me exactly?
...ly 1 sentence of technical content: "• EXPLAIN works on any DML not just SELECT (ie UPDATE, DELETE, and INSERT)". My biggest misunderstanding is what "startup" time means, and that's not explained anywhere in these ~30 slides.
– Mark E. Haase
Feb 19 '16 at 15...
Exclude folders from Eclipse search
...
In Eclipse Kepler there is a "Select a working set type" dialog that comes up after clicking New. (Worth noting that to find all types of file need to select "Resource" at this point.)
– Steve Chambers
Oct 8 '15 at 1...
How to build a query string for a URL in C#?
...om key in nvc.AllKeys
from value in nvc.GetValues(key)
select string.Format(
"{0}={1}",
HttpUtility.UrlEncode(key),
HttpUtility.UrlEncode(value))
).ToArray();
return "?" + string.Join("&", array);
}
I imagine there...
The cast to value type 'Int32' failed because the materialized value is null
...
where u.ID == userID
select (int?)ch.Amount).Sum() ?? 0;
This first casts to int? to tell the C# compiler that this expression can indeed return null, even though Sum() returns an int. Then we use the normal ?? operator to handle the null case....
Rails: How can I set default values in ActiveRecord?
...
See Paul Russell's comment on this answer for more details
If you're only selecting a subset of columns for a model (ie; using select in a query like Person.select(:firstname, :lastname).all) you will get a MissingAttributeError if your init method accesses a column that hasn't been included in the...
string.Join on a List or other type
...le<T>)
If you can't upgrade, you can achieve the same effect using Select and ToArray.
return string.Join(",", a.Select(x => x.ToString()).ToArray());
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...
Func vs. Action vs. Predicate [duplicate]
...s probably most commonly used in LINQ - for example in projections:
list.Select(x => x.SomeProperty)
or filtering:
list.Where(x => x.SomeValue == someOtherValue)
or key selection:
list.Join(otherList, x => x.FirstKey, y => y.SecondKey, ...)
Action is more commonly used for th...
How to compare dates in datetime fields in Postgresql?
... manipulation on the input string, correct? you don't need to be afraid:
SELECT *
FROM table
WHERE update_date >= '2013-05-03'::date
AND update_date < ('2013-05-03'::date + '1 day'::interval);
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How to do an INNER JOIN on multiple columns
...n once by giving the joined tables an alias, as in the following example:
SELECT
airline, flt_no, fairport, tairport, depart, arrive, fare
FROM
flights
INNER JOIN
airports from_port ON (from_port.code = flights.fairport)
INNER JOIN
airports to_port ON (to_port.code = flights.tair...